Traditionally used for
- Eye health
- Nerves & recovery
- Skin
Cautions & contraindications
- Pregnancy
- Toxic — professional use only
☯ TCM Properties
Dispels Wind and stops spasms; Removes superficial visual obstruction; Resolves toxins
Traditional Chinese Uses
She Tui (Periostracum Serpentis) is an animal-derived substance — the shed epidermal slough of non-venomous colubrid snakes, most commonly the beauty rat snake Elaphe taeniura. Sweet and salty with a neutral nature, entering the Liver channel, it dispels Wind and stops spasms, removes superficial visual obstruction (nebula/pterygium of the eye), and resolves toxicity. As a Wind-Damp/Wind-extinguishing agent it treats both internal Wind and Wind in the skin.
Classic uses include childhood convulsions, seizures and tetanic spasms; Wind rashes, itching, urticaria and stubborn sores including scabies and hard-to-heal boils (often applied topically); and superficial corneal opacities affecting vision. It is used in small doses, decocted (about 1.5-3 g) or, more commonly, powdered. The source species (Elaphe taeniura and related rat snakes) are widely distributed and not CITES-listed, but wild-collection pressures make farmed or reputably sourced material preferable.
Relationships
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Botanical Description
She Tui (also She Pi) is an animal-derived substance, not a plant: the shed epidermal skin (slough) of various non-venomous Chinese colubrid snakes, most commonly Elaphe taeniura Cope, Elaphe carinata (Günther), and Zaocys dhumnades (Cantor) (Colubridae). The slough is a thin, translucent, silvery-grey to pale yellow, semi-cylindrical, paper-like membrane often retaining the imprint of the original scale pattern, with conspicuous diamond-, hexagonal-, or oval-shaped scale outlines along the body and complete head and eye-cap impressions when intact. Sloughs are collected entire from snake habitats or breeding facilities, freed of dirt, and sun-dried; pieces are brittle, slightly lustrous, and odorless. In TCM, She Tui is used to dispel wind, relieve spasm, and remove screens (eye opacities); it is included in formulas for childhood convulsions, tetanus, and pruritic skin conditions. Sourcing should respect wildlife protection laws.
Active Constituents
Beta-keratin of the Oberhautchen and beta layer
Structural fibrous protein (glycine, proline and serine rich beta-keratin)Concentration: The dominant constituent by mass of the slough
The hard, brittle outer layers that give the slough its mechanical character. Infrared analysis of Periostracum serpentis shows the amide carbonyl band of beta-keratin near 1640 per centimetre and combined NH and OH stretching near 3270 per centimetre. Keratin is not absorbed and has no systemic pharmacology; the drug is essentially insoluble protein.
Alpha-keratin of the inner alpha layer
Structural fibrous proteinConcentration: Thinner protein layer beneath the lipid-rich mesos layer
The softer, more pliant keratin fraction of the shed epidermis. Together with the beta layer it accounts for the observation that shed skin is an avid cation-binding material.
Epidermal lipids of the mesos layer, including cholesterol and its derivatives
Sterols and epidermal lipidsConcentration: Minor fraction concentrated in the mesos layer
The lipid barrier layer of the shed epidermis. In work on the shed skin of a different colubrid, the hexane extract, which is the lipid-rich fraction, was the one with the strongest antiproliferative effect on a melanoma cell line in vitro, so what solvent-extractable activity the slough has appears to sit in this fraction rather than in the keratin.
Adsorbed metal ions
Inorganic trace elementsConcentration: Variable and environment-dependent; not standardised
Keratinous shed snake skin behaves as a strong biosorbent. Tested as an adsorbent for uranyl ion it reached a capacity of 0.377 mol per kilogram with an optimum around pH 4 to 5. That is materials science, but it has a direct quality-control consequence: a keratin sheet that binds heavy metal cations this efficiently will carry whatever cations its environment offered, which is why trace-element determination in Periostracum serpentis has been a subject of method development.
⚠ Drug Interactions
Corpus Agkistrodontis, Qi She, Wu Shao She and other whole-snake drugs
She Tui is the shed epidermis, not the animal. It is a sheet of dead keratin that the snake walks out of; it contains no muscle, no organ tissue, no blood and no venom apparatus. A whole-snake drug is the carcass. The two have different constituent profiles, different traditional indications and different safety considerations, and evidence about one cannot be carried across to the other. The Chinese Pharmacopoeia recognises the slough from three colubrids, Elaphe taeniura Cope, Elaphe carinata (Guenther) and Zaocys dhumnades (Cantor), so even within the slough drug the species named in a prescription is one of three permitted origins.
Clinical note: Read the prescription for the part, not just the pinyin. She Tui at 1.5 to 6 grams in decoction, or 0.3 to 0.6 grams as powder, is a different order of exposure from a whole-snake drug and should not be dose-substituted for one.
Pregnancy
The drug is classified as toxic in the traditional literature and is contraindicated in pregnancy in the standard English-language and Chinese materia medica entries. No reproductive toxicology study has been performed on the slough, so the contraindication rests on classical usage rather than on data. Absence of an assay is not evidence of safety.
Clinical note: Do not prescribe in pregnancy or when pregnancy is possible, and ask before dispensing.
Species substitution in the slough trade
A dried slough retains scale pattern impressions but loses almost every feature a bench identification would use, and it is the cheapest possible thing to counterfeit because sloughs are shed by every snake. Adulteration has been measured in the whole-snake medicinal trade, where a barcode and high-resolution melting method applied to seventy-three Chinese samples across four families and thirteen genera detected adulterants at the 1.6 percent level; the same commercial pressures apply here. The redeeming point is that shed epidermis is a validated non-invasive source of amplifiable genomic DNA in snakes, so molecular authentication of a slough is entirely feasible and is the only reliable route.
Clinical note: Ask the supplier which of the three pharmacopoeial colubrids the material is from and whether it has been authenticated molecularly. Morphological certificates on dried slough are worth very little.
Immunosuppressant and immunomodulator therapy
Extracts of shed snake skin are immunologically active in vitro. In murine lymphocyte culture, shed skin extract of Elaphe sauromates raised tumour necrosis factor alpha and interferon gamma produced by CD3 positive T cells under anti-CD3 and anti-CD28 or lipopolysaccharide stimulation, an effect requiring the presence of non-T cells, and suppressed transforming growth factor beta gene expression. That study used a different species, an organic solvent extract rather than a decoction, and mouse cells, so it cannot be translated into a human dosing statement; it does establish that the material is not immunologically inert.
Clinical note: No action is needed on this evidence alone. Note it only if a patient on ciclosporin, tacrolimus or a biologic has an unexplained inflammatory flare while taking the herb.
Conservation and legal status of the source animal
Elaphe taeniura is assessed as Vulnerable on the IUCN Red List, on the basis of a suspected population decline exceeding 30 percent over ten years, principally in China, driven by overexploitation for the food and skin trade. It is not on the CITES appendices, so international movement of the slough is not CITES-controlled, but the source population is declining. The slough itself is the one part of a snake that can be collected without killing the animal, from farmed or captive stock, which makes provenance a meaningful question rather than a rhetorical one.
Clinical note: Ask whether the slough is collected from farmed animals. This is the rare animal drug where a genuinely non-lethal supply chain is possible, and it is worth insisting on.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 3–6 g | Daily | — | — | Standard oral dose per Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 113–114. Exact wording: Normally, 3–6 g is decocted with water as an oral |
Evidence Tier
Limited evidence · 2 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
2
1 verified · 1 unverified
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Investigation of immunomodulatory and cytotoxic effects of shed snake skin (Elaphe sauromates) extract
Hexane, methanol and chloroform extracts of shed snake skin were tested on L929 fibroblasts and SK-MEL-30 melanoma cells and on murine lymphocytes. The hexane extract was the most antiproliferative against SK-MEL-30 at low concentrations. Extract treatment increased tumour necrosis factor alpha and interferon gamma from CD3 positive T cells under stimulation, an effect that required non-T cells to be present and was absent on purified CD4 positive T cells, and it blocked transforming growth factor beta gene expression without changing regulatory T cell generation. The species used was Elaphe sauromates, a Eurasian rat snake, not the pharmacopoeial Elaphe taeniura, and the authors describe it as the first in vitro study of these effects.
Investigation of adsorption properties of Periostracum serpentis as keratin-containing natural biowaste composite material for uranium
Shed snake skin was characterised by scanning electron microscopy, infrared spectroscopy, surface area analysis and energy-dispersive X-ray spectroscopy and tested as an adsorbent for uranyl ion. Adsorption capacity reached 0.377 mol per kilogram, kinetics followed the Elovich model, and uptake was maximal around pH 4 to 5 and spontaneous. The study is about water treatment, but it quantifies how strongly this keratin binds metal cations, which is the relevant fact for contamination of the drug.
⚠ Safety & Contraindications
- Pregnancy
- Toxic — professional use only
Contraindications
Its use is prohibited in pregnant women.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 113–114.
Historical Texts
Shen Nong Ben Cao Jing (Divine Husbandman's Classic of Materia Medica), insect and fish section
Han dynasty compilation, circa 200 CEBen Cao Gang Mu (Compendium of Materia Medica), Li Shizhen, scale section, second scale chapter
Ming dynasty, 1596Pharmacopoeia of the People's Republic of China, Serpentis Periostracum (She Tui)
Modern, 2020 editionReferences
- IUCN. Elaphe taeniura: Li, P., Zhou, Z. & Ghosh, A. . IUCN Red List of Threatened Species (2021) [DOI]
- Yang L, Li Y, Guo X, Ma X, Yan Q. COMPARISON OF DRY ASHING, WET ASHING AND MICROWAVE DIGESTION FOR DETERMINATION OF TRACE ELEMENTS IN PERIOSTRACUM SERPENTIS AND PERIOSTRACUM CICADAE BY ICP-AES . Journal of the Chilean Chemical Society (2013) [DOI]
- Yanqing C, Bo W, Ping W, Bisheng H, Hegang L, Chao X, Mingli W, Nili W, Di L, Zhigang H, Shilin C. Rapid identification of common medicinal snakes and their adulterants using the Bar-HRM analysis method . Mitochondrial DNA Part A (2019) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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